A Merry Mirthworm Christmas is an animated television special, produced by Perennial Pictures. It premiered on the Showtime Cable Network on December 14, 1984. The film features a cast of Mirthworms, which are described as anthropomorphic worms about 2 in (51 mm) long, who live in the tiny town of Wormingham. Mirthworms tend to use proper nouns that play on the word "worm". The characters live in the town of Wormingham, the main character is named Burt Worm, and the antagonist is named Wormaline Wiggler.

The show was followed by two additional Mirthworm specials, A Mirthworm Masquerade (1987) and Mirthworms on Stage (1989).